Process for the manufacture of the lower aliphatic esters of pantothenic acid



Patented Nov. 10, 1942 7 PROCESS FOR THE MANUFACTURE OF THE LOWER ALIPHATIO ESTERS OF PANTO- THENIC ACID Andr Studer, Basel, Switzerland No Drawing. Application October 28, 1941, Serial In Switzerland December 24,

2 Claims. (Cl. 260-482) It is known that pantothenic acid can be obtained by condensation of fl-alanine (fi-aminopropionic acid) with -hydro y.-B,fi-dimethyl-'ybutyrolactone (Science. vol. 91, year 1940, page 246; Journal of the American Chemical Society, vol. 62, year 1940, pages 1628, 1784, 1785, 2251).

The corresponding preparation oi esters of pantothenic acid is rendered diflicult by the fact that the esters of p-alanlne to be used as starting materials possess various properties which render them unsuitable or inconvenient for technical use. They are unstable in-the free state or in form of salts so that they cannot be stored. Consequently, they must .be employed immedi-' ately after preparation. Moreover, the free esters easily tend to form crystalline polymerisation products (Recueil des' Travaux Chimiques des Pays-Bas, vol. 25, year 1906, page'79; Zeitschriit iiir Physiologische Chemie, vol. 85, year 1913, Me 118). Their salts are usually 11318 sccpic and then easily sapcnify to reform tree p-alanine, sometimes even on storing in a desiccator (Archiv der Pharmazie, vol. 242, year 1904, page 610). Furthermore, the preparation and purification of the p-alanine esters is a technicallyvery complicated measure which also entails losses (Zeitschrift fiir Physiologische Chemie, vol. 85, year 1913, P e 117) It has now been found that the esters of pantotlienic acid can be obtained without the discHP-c cnon (1 1 i NOI-CHI 'CHr-COOR an,

cm nocnr-e-- onon n5- o-mmcum-cooa In this manner esters of pantothenic acid are readily obtained which was the less to be expected since the formation of p-amino-propionic acid from p-nitro-propionic acid by means of catalytically activated hydrogen has hitherto not been described in the literature. It could, therefore, not be anticipated that the manufacture of esters of pantothenic acid would manner indicated. y

In tests carried out on the growth of rats and other animals, the same results are obtained with 5 the esters of pantothenic acid as with free pantothenic acid.

succeed in the Example 1 130 parts by weight of c-hydrnxy-Bfi-ditnethyl-y-butyrolactone are treated with 147 parts by weight of fl-nitro-propionic acid ethyl ester in 500 parts by weight of methanol with a platinum or 'palladium catalyst in a pressure vessel with hydrogen under pressure at 90100 C. when 6 mols of hydrogen have been taken up, the hydrogenation ceases. After cooling, the product is sucked oil from the catalyst and the filtrate evaporated to dryness. The pantothenic acid ethyl ester is thus obtained as a clear syrup.

20 If the levorotatory lactone is used as starting 0 material, a dextrorotatory pantothenic acid ester is obtained.

Example 2 in 500 parts by weight of methanol with a nickel catalyst in a pressure vessel with hydrogen at Bil-100 C. and a gauge pressure of 20-40 atm. When 6 mols of hydrogen have been taken up, the hydrogenation ceases. After cooling, the product is sucked oil from the catalyst and the filtrate evaporated to dryness. Ayellow oil is obtained which, after distillation in a molecular still, yields pantothenic acid methyl ester as a colourless syrup.

I claim: I 1. Process for the manufacture or the lower aliphatic esters of pantothenic acid, comprising causing catalytically activated hydrogen to act on the lower aliphatic esters of fi-niIa'o-propionic acid inpresence of a-hydroxy-fip-dimethyl-w-butyrolactone at raised temperatures.

2. Process for the manufactur of the lower 4 aliphatic esters otpantothenic acid, comprising causing catalytically activated hydrogen to act on the lower aliphatic esters of fl-nitro-propionic acid in presence of a-hydroxy-fi,fldirnethyl-ybutyrolactone at raised temperatures under-v ressure and in presence of a solvent.

ANDRE s'runm. 

